In the past, with respect to area lighting, such as illumination of parking lots and roads, billboard signs spotlighting of particular areas such as a yard in a residential area, and the like, a light source such as a mercury vapor or low pressure sodium bulb driven by a ballast or voltage step-up transformer and mounted in a fixture attached to a tall pole is the preferred way to achieve such illumination. However, this mounting arrangement creates problems, the most obvious of which is the instance wherein the light source fails. In a parking lot illumination fixture or a fixture attached to a utility pole, the poles are generally on the order of 40 feet or more, requiring a truck having a bucket lift in order to lift a person to the fixture and replace the bulb or to effect repairs on the fixture. Typically, the cost of this service, merely to replace a bulb in a parking lot fixture, is about $150.00 per bulb, with repairs to the fixture being much more expensive. With lighting fixtures for illuminating billboard or backlit type signs, it is necessary for a person to be lifted, as by a bucket lift, or climb a ladder or a pole in order to reach the sign. In the instance where the sign is a backlit type, panels of the sign must be disassembled prior to replacing the bulbs and/or ballast. In a residential application, where a homeowner illuminates a yard area by a lighting fixture attached to a pole, when the light bulb fails, the resident must either hire a bucket lift truck or risk life and limb by the questionable technique of propping a ladder against a pole or climb the pole to change the bulb. Even in the application where lighting fixtures are mounted under eaves of a house, when a bulb fails, the resident must climb a ladder or otherwise stand on something in order to gain access to the fixture.
In addition to the obvious problem of maintenance, the lighting fixtures themselves are sometimes heavy contrivances having a ballast mounted internally and requiring sturdy poles in order to support the fixtures. In other instances, the fixtures are mounted in a cantilevered manner, again requiring sturdy poles which may require bracing, as by guy wires. Further, during installation, wiring must be run the length of the pole and secured, adding to the cost of the fixture and installation.
In general, the approach of mounting a lighting fixture and bulb at the top of a tall pole or on the side of a building, while heretofore necessary to disperse light from above, creates expensive maintenance problems, poses hazards to those attending to such problems, and requires poles constructed so as to support the fixture.
Accordingly, it is the object of this invention to provide an area lighting fixture having the light source mounted generally at ground level, providing convenient accessability to both the bulb, bulb fixture, and when used, the ballast.